1. Field of the Invention
The present invention relates to a photosensitive resin composition, a printed wiring board, a substrate for disposing semiconductor chips, a semiconductor device and processes for producing a printed wiring substrate, a substrate for disposing semiconductor chips and a semiconductor device. More particularly, the present invention relates to a photosensitive resin composition of the negative type which can be applied to production of semiconductor elements and circuit wiring boards, can exhibit high sensitivity and high resolution and can form resin layers having excellent heat resistance; a printed wiring substrate, a substrate for disposing semiconductor chips and a semiconductor device obtained by using the photosensitive resin composition; and processes for producing a printed wiring substrate, a substrate for disposing semiconductor chips and a semiconductor device using the photosensitive resin composition.
2. Description of Related Art
As electronic instruments are recently used in portable forms, electronic instruments rapidly become lighter, thinner, shorter and smaller and have more advanced functions. Due to the above progress, semiconductor elements become smaller and more highly integrated. For example, in semiconductor circuits formed on semiconductor chips, the circuits themselves are more highly integrated, the circuits become finer due to the decrease in the size of packages and materials sealing the packages to protect chips become thinner. It is generally conducted that protecting layers such as passivation layers are used on circuits at the surface of chips to assure the reliability. To achieve further integration, circuits are formed in multi-layers with inter-layer insulation disposed between the layers.
With respect to semiconductor packages in which semiconductor chips are sealed, new packaging technologies which can achieve integration to high densities such as the ball grid array (BGA), the chip scale package (CSP) and the multi-chip module (MCM) have been developed. In these semiconductor packages, electric connection between electrodes in semiconductor chips and printed wiring boards is achieved by using interposers which are substrates constituted with various materials such as plastic and ceramics. Because the circuits formed on the substrates are introduced into the inside of semiconductors having decreased sizes, the circuits have much finer wiring and much higher degree of integration than those in conventional printed wiring circuits. Therefore, it is necessary that the fine circuits be protected by adopting the form of packaging. New technologies are developed also with respect to printed wiring boards to which these semiconductor packages are disposed. For example, in the build-up process, wiring layers are successively formed on a substrate with an insulation resin disposed between the layers to increase the density of wiring.
It is commonly required for these protecting resins and inter-layer insulation resins that the resins have high heat resistance so that the resin can withstand temperatures as high as 200 to 300xc2x0 C. during bonding and disposing chips and workability in formation of holes so that electric conductivity is provided at junctions of wirings and between insulation layers. In particular, with respect to protecting films for interposers and inter-layer insulation films for circuit boards formed in accordance with the build-up process which must be worked on substrates, it is required that the resins have workability at low temperatures so that the working does not cause damage to the substrates.
Heretofore, polyimides have been used for applications which require heat resistance such as protecting films of semiconductor chips and epoxy resins have been used for applications which require working at low temperatures such as protecting films on circuit substrates and inter-layer insulation films. For pattern working such as formation of holes suitable for highly integrated circuit wiring, it is advantageous that the patterns are formed by utilizing the photomechanical process (the photographic process), i.e., by using photosensitive resins such as heat resistant photosensitive polyimide and epoxy resins.
As for the polyimide resins, photosensitive polyimides have been developed and used (for example, Japanese Patent Application Publication Showa 55(1980)-30207 and Japanese Patent Application Laid-Open No. Showa 54(1979)-145794). In general, these photosensitive polyimides form crosslinked structures by photoradical polymerization of (metha)acrylates introduced into the carboxyl group of polyamic acid which is used as the precursor of the polyimide. Pattern working such as formation of holes is conducted by utilizing the difference in solubility into developer between crosslinked area and uncrosslinked area. When the above polyamic acid is converted into a polyimide, it is necessary that the (metha)acryloyl group bonded to the carboxyl group be removed. Therefore, the ring closure for forming such an imide structure from the polyamic acid requires stronger heating than that required for the ring closure for forming conventional polyimides. Moreover, because the properties of the polyimide such as heat resistance and mechanical properties are markedly deteriorated when the removed (metha)acrylate fragment is left remaining in the polyimide, the removed (metha)acrylate fragment must be decomposed and vaporized at high temperature in order that the polyimide can exhibit the excellent characteristic properties thereof. Thus, it is necessary that the photosensitive polyimides be worked at temperatures still higher than those for conventional polyimides. To overcome the problem of working at high temperatures, it has been proposed that (metha)acrylate moiety are incorporated into side chains of polyimides which has been treated by ring closure in advance so that low temperature workability is excellent (Japanese Patent Application Laid-Open No. Showa 59(1984)-108031 and the like other applications). However, the (metha)acrylate moiety are left remaining in these resins after working and the properties such as heat resistance deteriorate.
As for the epoxy resins, various types of photosensitive epoxy resins are actually used as solder resists for protection of circuit wirings and resins for inter-layer insulation for the build-up process. However, no epoxy resins exhibit satisfactory properties such as heat resistance and flexibility to follow deformation of thinner substrates contained in thinner packages.
As the photosensitive material composition advantageously used for resists exhibiting high resolution and high sensitivity, a photosensitive material composition comprising a fullerene without photosensitive groups and a photosensitive agent such as a diazide compound has been proposed (Japanese Patent No. 2814174). However, this composition has drawbacks in that the solution of the composition has low viscosity because the composition is composed of a fullerene and a low molecular weight diazide so it is difficult to coat an uniform film having a sufficient thickness. And the coating film formed by polymerization and crosslinking between the fullerene and the diazide has inferior mechanical strength and poor heat resistance. Moreover, that a fullerene which is very expensive at the present time is used in an amount five folds as much as the amount of the diazide to cause economic disadvantage.
An object of the present invention is to provide a photosensitive resin composition of the negative type which can be applied to production of semiconductor elements and circuit wiring boards, exhibits high sensitivity and high resolution and can form resin layers having excellent heat resistance; a printed wiring board, a substrate for disposing semiconductor chips and a semiconductor device using the photosensitive resin composition; and processes for producing a printed wiring board, a substrate for disposing semiconductor chips and a semiconductor device using the photosensitive resin composition.
As the result of extensive studies by the present inventors to overcome the above problems, it was found that a photosensitive resin composition having remarkably improved photosensitivity and heat resistance can be obtained by using a polyamic acid or polyimide having a cis-diene structure at side chains in combination with an oxygen sensitizer and that a resin layer having excellent heat resistance can be formed by forming a layer of the photosensitive resin composition, applying radiation to the oxygen sensitizer and crosslinking the cis-diene group by following oxidation polycondensation with singlet oxygen generated by exposure of radiation to the oxygen sensitizer in the presence of oxygen. The present invention has been completed based on this knowledge.
The present invention provides:
(1) A photosensitive resin composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [1]: 
xe2x80x83wherein at least one of R1, R2, R3 and R4 represents a monovalent organic group having a cis-diene structure; and the rest of R1, R2, R3 and R4 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms;
(2) A photosensitive resin composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [2]: 
xe2x80x83wherein at least one of R5, R6, R7, R8, R9, R10, R11 and R12 represents a monovalent organic group having a cis-diene structure; and the rest of R5, R6, R7, R8, R9, R10, R11 and R12 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms;
(3) A photosensitive resin composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [3]: 
xe2x80x83wherein at least one of R13, R14, R15, R16, R17, R18, R19 and R20 represents a monovalent organic group having a cis-diene structure; the rest of R13, R14, R15, R16, R17, R18, R19 and R20 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; and R21 represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group having 1 to 4 carbon atoms;
(4) A photosensitive resin composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [4]: 
xe2x80x83wherein at least one of R22, R23, R24 and R25 represents a monovalent organic group having a cis-diene structure; the rest of R22, R23, R24 and R25 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; X1 and X2 each independently represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which each has 1 to 4 carbon atoms and may have substituents; Ar1 and Ar2 each independently represents a divalent aromatic group; and l1, l2, m1 and m2 each independently represents 0 or 1 except that m1 represents 1 when l1 represents 1 and m2 represents 1 when l2 represents 1;
(5) A photosensitive resin composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [5]: 
xe2x80x83wherein at least one of R26, R27, R28, R29, R30, R31, R32 and R33 represents a monovalent organic group having a cis-diene structure; the rest of R26, R27, R28, R29, R30, R31, R32 and R33 each independently represents hydrogen atom, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; Y1 represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which each has 1 to 4 carbon atoms and may have substituents; and n1 represents 0 or 1;
(6) A photosensitive resin composition described in any of (1), (2), (3), (4) and (5), wherein the cis-diene structure is a cyclopentadiene, furan, thiophene or pyrrole structure;
(7) A photosensitive resin composition described in any of (1), (2), (3), (4), (5) and (6), wherein the oxygen sensitizer is a fullerene;
(8) A printed wiring board which is prepared by coating a printed wiring substrate with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by exposure of radiation;
(9). A substrate for disposing semiconductor chips which is prepared by coating a printed wiring substrate with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by exposure of radiation;
(10) A semiconductor device which is prepared by coating a substrate on which semiconductor chips are disposed with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by exposure of radiation;
(11) A process for producing a printed wiring board which comprises coating a printed wiring substrate with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by crosslinking the cis-diene group by following oxidation polycondensation with singlet oxygen generated by exposure of radiation to the oxygen sensitizer in the presence of oxygen;
(12) A process for producing a substrate for disposing semiconductor chips which comprises coating a printed wiring substrate with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by crosslinking the cis-diene group by polycondensation with oxidation with singlet oxygen generated by exposure of radiation to the oxygen sensitizer; and
(13) A process for producing a semiconductor device which comprises coating the surface for forming a conductive circuit of a substrate on which semiconductor chips are disposed with a photosensitive resin composition described in any of (1), (2), (3), (4), (5), (6) and (7), and forming fine patterns by crosslinking the cis-diene group by polycondensation with oxidation with singlet oxygen generated by exposure of radiation to the oxygen sensitizer.
The preferable embodiments of the present invention include:
(14) A photosensitive resin composition described in (1), wherein the content of the structural unit represented by formula [1] is 30% by mol or more of the total diamine units;
(15) A photosensitive resin composition described in (2), wherein the content of the structural unit represented by formula [2] is 30% by mol or more of the total diamine units;
(16) A photosensitive resin composition described in (3), wherein the content of the structural unit represented by formula [3] is 30% by mol or more of the total diamine units;
(17) A photosensitive resin composition described in (4), wherein the content of the structural unit represented by formula [4] is 30% by mol or more of the total diamine units;
(18) A photosensitive resin composition described in (5), wherein the content of the structural unit represented by formula [5] is 30% by mol or more of the total diamine units;
(19) A photosensitive resin composition described in any of (1), (2), (3), (4) and (5), wherein the molecular weight of the polyamic acid or the polyimide is 5,000 or greater; and
(20) A photosensitive resin composition described in any of (1), (2), (3), (4) and (5), wherein the amount of the oxygen sensitizer is 0.01 to 20 parts by weight per 100 parts by weight of the polyamic acid or the polyimide.
The first embodiment of the photosensitive resin composition of the present invention is the composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [1]: 
In general formula [1], at least one of R1, R2, R3 and R4 represents a monovalent organic group having a cis-diene structure; and the rest of R1, R2, R3 and R4 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms.
The second embodiment of the photosensitive resin composition of the present invention is the composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [2]: 
In general formula [2], at least one of R5, R6, R7, R8, R9, R10, R11 and R12 represents a monovalent organic group having a cis-diene structure; and the rest of R5, R6, R7, R8, R9, R10, R11 and R12 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms.
The third embodiment of the photosensitive resin composition of the present invention is the composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [3]: 
In general formula [3], at least one of R13, R14, R15, R16, R17, R18, R19 and R20 represents a monovalent organic group having a cis-diene structure; the rest of R13, R14, R15, R16, R17, R18, R19 and R20 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; and R21 represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group having 1 to 4 carbon atoms.
The fourth embodiment of the photosensitive resin composition of the present invention is the composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [4]: 
In general formula [4], at least one of R22, R23, R24 and R25 represents a monovalent organic group having a cis-diene structure; the rest of R22, R23, R24 and R25 each independently represents hydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; X1 and X2 each independently represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which each has 1 to 4 carbon atoms and may have substituents; Ar1 and Ar2 each independently represents a divalent aromatic group; and l1, l2, m1 and m2 each independently represents 0 or 1 except that m1 represents 1 when l1 represents 1 and m2 represents 1 when l2 represents 1.
The fifth embodiment of the photosensitive resin composition of the present invention is the composition which comprises an oxygen sensitizer and a cis-diene-substituted polyamic acid or polyimide having a structural unit represented by general formula [5]: 
In general formula [5], at least one of R26, R27, R28, R29, R30, R31, R32 and R33 represents a monovalent organic group having a cis-diene structure; the rest of R26, R27, R28, R29, R30, R31, R32 and R33 each independently represents hydrogen atom, hydroxyl group, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; Y1 represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which has 1 to 4 carbon atoms and may have substituents; and n1 represents 0 or 1.
In the fourth and fifth embodiments of the composition of the present invention, the cis-diene-substituted polyamic acid or polyimide having the structural unit represented by general formula [4] and [5], respectively, are characterized in that the main chain is bonded to the meta-positions of an aromatic ring substituted with a monovalent organic group having the cis-diene structure. When the main chain is bonded to the meta-positions of the aromatic ring, molecular packing such as crystallinity of the polyamic acid or the polyimide tends to decrease. In particular, the resin having the cis-diene structure shows improved solubility in a developer. As the result, when optical patterns are formed, the difference in solubility into a developer between unexposed portions which should be dissolved into the developer and exposed portions which are crosslinked is remarkably exhibited. Therefore, the ability to form patterns is remarkably improved in that excellent contrast is exhibited by exposure to a small amount of light, resin patterns having excellent shapes are easily obtained and resins of the unexposed portions can be removed completely.
In the composition of the present invention, the polyamic acid or the polyimide may have a single type of the structural unit represented by any of general formulae [1] to [5] or two or more types of such structural units in the form of a copolymer. The composition of the present invention may comprise a single type or a mixture of two or more types of the cis-diene-substituted polyamic acids or polyimides having the structural units represented by general formulae [1] to [5]. The composition of the present invention may be a mixture of the cis-diene-substituted polyamic acids or polyimides having the structural units represented by general formulae [1] to [5] and polyamic acids or polyimides having no structural units represented by general formulae [1] to [5].
Examples of the monovalent organic group having a cis-diene structure in general formulae [1] to [5] include xe2x80x94CH2Oxe2x80x94COxe2x80x94D, xe2x80x94Oxe2x80x94COxe2x80x94D, xe2x80x94COxe2x80x94Oxe2x80x94CH2D, xe2x80x94CH2Oxe2x80x94CH2xe2x80x94D, xe2x80x94Oxe2x80x94CH2xe2x80x94D, xe2x80x94NHxe2x80x94COxe2x80x94D and xe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94D. D represents a cis-diene structure. Examples of the cis-diene structure represented by D include cyclopentadienyl group, furyl group, pyrrolyl group, thienyl group, 2,4-pyranyl group, isobenzofuranyl group, indolydinyl group and quinolidinyl group. Among these groups, cyclopentadienyl group, furyl group, thienyl group and pyrrolyl group are preferable.
In general formulae [1] to [5], examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group and lauryl group. Among these groups, methyl group, ethyl group, propyl group, butyl group and pentyl group are preferable.
In general formulae [1] to [5], examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, lauryloxy group and phenoxy group. Among these groups, methoxy group, ethoxy group, butoxy group and pentyloxy group are preferable.
In general formulae [3] to [5], examples of the alkylene group having 1 to 4 carbon atoms include methylene group, ethylene group, propylene group, isopropylidene group and butylene group. Examples of the alkyleneoxy group having 1 to 4 carbon atoms include methyleneoxy group, ethyleneoxy group, propyleneoxy group and butyleneoxy group.
The process for producing the cis-diene-substituted polyamic acids and polyimides having structural units represented by general formulae [1] to [5] which are used in the present invention is not particularly limited. For example, the polyamic acid and the polyimide can be produced by using a diamine represented by one of general formulae [6] to [10] and a dianhydride of a polycarboxylic acid as the materials. 
In general formula [6], at least one of R34, R35, R36 and R37 represents hydroxyl group; and the rest of R34, R35, R36 and R37 each independently represents hydrogen, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms.
In general formula [7], at least one of R38, R39, R40, R41, R42, R43, R44 and R45 represents hydroxyl group; and the rest of R38, R39, R40, R41, R42, R43, R44 and R45 each independently represents hydrogen, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms.
In general formula [8], at least one of R46, R47, R48, R49, R50, R51, R52 and R53 represents hydroxyl group; the rest of R46, R47, R48, R49, R50, R51, R52 and R53 each independently represents hydrogen, carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; and R54 represents oxygen, sulfur, an alkylene group, an alkylidene group or an alkyleneoxy group having 1 to 4 carbon atoms.
In general formula [9], at least one of R55, R56, R57 and R58 represents hydroxyl group, hydroxymethyl group or carboxyl group; the rest of R55, R56, R57 and R58 each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; X3 and X4 each independently represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which each has 1 to 4 carbon atoms and may have substituents; Ar3 and Ar4 each independently represents a divalent aromatic group; and l3, l4, m3 and m4 each independently represents 0 or 1 except that m3 represents 1 when l3 represents 1 and m4 represents 1 when l4 represents 1.
In general formula [10], at least one of R59, R60, R61, R62, R63, R64, R65 and R66 represents hydroxyl group, hydroxymethyl group or carboxyl group; the rest of R59, R60, R61, R62, R63, R64, R65 and R66 each independently represents hydrogen, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; Y2 represents oxygen, sulfur or an alkylene group, an alkylidene group or an alkyleneoxy group which each has 1 to 4 carbon atoms and may have a substituent; and n2 represents 0 or 1. Atoms substituting hydrogen such as chlorine are included in the substituent.
Examples of the diamine represented by general formula [6] include 2-hydroxy-3-methyl-1,4-phenylenediamine and the like. Examples of the diamine represented by general formula [7] include 2,2xe2x80x2-dihydroxy-3,3xe2x80x2-dimethyl-4,4xe2x80x2-diaminobiphenyl and the like. Examples of the diamine represented by general formula [8] include 2,2-bis(3-hydroxy-4-aminophenyl)propane and the like. Examples of the diamine represented by general formula [9] include 3,5-diaminobenzyl alcohol, 3,5-diaminophenol and 3,5-diaminobenzoic acid. Examples of the diamine represented by general formula [10] include 3,3xe2x80x2-diamino-4,4xe2x80x2-dihydroxybiphenyl, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 3,5-bis(4-aminophenoxy)benzyl alcohol.
In the present invention, the dianhydride of a polycarboxylic acid which is reacted with the diamines represented by general formulae [6] to [10] is not particularly limited. Examples of the dianhydride of a polycarboxylic acid include pyromellitic dianhydride, prehnitic dianhydride, 3,3xe2x80x2,4,4xe2x80x2-benzophenonetetracarboxylic dianhydride, 3,3xe2x80x2,4,4xe2x80x2-biphenyltetracarboxylic dianhydride, 4,4xe2x80x2-hexafluoroisopropylidene-diphthalic anhydride, benzenepentacarboxylic dianhydride and mellitic dianhydride. Among these compounds, 4,4-hexafluoroisopropylidene-diphthalic dianhydride is preferably used.
In the present invention, the process for reacting the diamines represented by general formulae [6] to [10] with the dianhydride of a polycarboxylic acid is not particularly limited. The polyamic acid can be synthesized in accordance with a conventional process of polymerization. For example, a polyamic acid having a structural unit represented by general formula [11] can be obtained by reacting a diamine represented by general formula [6] with pyromellitic dianhydride in a solvent such as N-methyl-2-pyrrolidone at the room temperature. A polyimide having a structural unit represented by general formula [12] can be obtained by the ring closure reaction with dehydration of the polyamic acid having a structural unit represented by general formula [11]. A polyamic acid having a structural unit represented by general formula [13] can be obtained by reacting a diamine represented by general formula [9] with pyromellitic dianhydride in a solvent such as N-methyl-2-pyrrolidone. A polyimide having a structural unit represented by general formula [14] can be obtained by the ring closure reaction with dehydration of the polyamic acid having a structural unit represented by general formula [13]. 
The process for incorporating a monovalent organic group having a cis-diene structure into the polyamic acid having a structural unit represented by general formula [11] or [13] or into the polyimide having a structural unit represented by general formula [12] or [14] is not particularly limited. For example, a monovalent organic group having a cis-diene structure can be incorporated into hydroxyl group of the polyamic acid having a structural unit represented by general formula [11] or [13] or the polyimide having a structural unit represented by general formula [12] or [14] by reacting a halogenated compound having the cis-diene structure in the presence of a base. When, in general formula [11], R34 represents methyl group, R35 represents hydroxyl group, R36 and R37 each represents hydrogen and the halogenated compound having the cis-diene structure is furfuryl bromide, the polyamic acid having a structural unit represented by the formula [15] can be obtained. When, in general formula [13], R57 represents hydroxyl group, R55, R56 and R58 each represents hydrogen and the halogenated compound having the cis-diene structure is furfuryl bromide, the polyamic acid having a structural unit represented by general formula [16] can be obtained. 
In the present invention, as the process for producing the cis-diene-substituted polyamic acids having a structural units represented by general formulae [1] to [5], a diamine having hydroxyl group can be reacted with a dianhydride of a polycarboxylic acid and then an organic group having a cis-diene structure can be incorporated into the obtained product, as described above. Alternatively, for example, a diamine having an organic group having a cis-diene structure may be reacted with a dianhydride of a polycarboxylic acid. Examples of the diamine having an organic group having a cis-diene structure include 2,5-diamino-6-furfuryloxytoluene, 3,3xe2x80x2-difurfuryloxy-4,4xe2x80x2-diaminobiphenyl, 2,2-bis(3-furfuryloxy-4-aminophenyl)propane, 3,5-diaminobenzyl-2-furoate, 1,1,1,3,3,3-hexafluoro-2,2-bis(3-amino-4-furfuryloxyphenyl)propane, 3,3xe2x80x2-diamino-4,4xe2x80x2-di(2-furoylamino)biphenyl and 3,3xe2x80x2-diamino-4,4xe2x80x2-difurfuryloxybiphenyl. The above diamines can be obtained, for example, by reacting an aromatic dinitro compound having hydroxyl group, carboxyl group or a hydroxyalkyl group with a halogenated compound having a cis-diene structure such as furfuryl bromide in the presence of a base, followed by reducing the nitro group in the product. The process for reducing nitro group is not particularly limited. Examples of the process for reducing nitro group include reduction with hydrazine, catalytic hydrogenation reaction in the presence of a transition metal catalyst such as nickel, palladium and platinum and reduction with an aqueous solution of indium and ammonium chloride.
In the composition of the present invention, examples of the structural unit represented by general formula [4] include structural units expressed by the following formulae [4-(1)] to [4-(20)] and examples of the structural unit represented by general formula [5] include structural units expressed by the following formulae [5-(1)] to [5-(10)]. 
In the composition of the present invention, it is preferable that the amount of the structural units represented by general formulae [1] to [5] is 30% by mol or more, more preferably 50% by mol or more and most preferably 60% by mol or more of the total amount of the diamine structural units. When the amount of the structural units represented by general formulae [1] to [5] is less than 30% by mol of the total amount of the diamine structural units, there is the possibility that the curing property of the photosensitive resin composition deteriorates. In the present invention, it is preferable that the molecular weight of the cis-diene-substituted polyamic acids and polyimides having structural units represented by general formulae [1] to [5] are 5,000 or greater, more preferably 10,000 to 1,000,000 and most preferably 50,000 to 200,000. When the molecular weight of the polyamic acids and the polyimides are smaller than the above value, there is the possibility that obtaining a uniform film becomes difficult. When the molecular weight of the polyamic acids and the polyimides are excessively great, there is the possibility that solubility decreases and forming a uniform film becomes difficult.
The cis-diene-substituted polyamic acids and polyimides having the structural units represented by general formulae [1] to [5], which are used in the composition of the present invention, are soluble in solvents or alkaline aqueous solutions. The polyamic acids and the polyimides easily react with the singlet oxygen generated by the effect of the oxygen sensitizer and intermediates of polyamic acids and the polyimides, respectively, having a peroxide group are formed. The formed intermediates immediately react with the adjacent polyamic acids and the polyimides, respectively, induce crosslinking between each other by polycondensation and remarkably increase the molecular weight. Due to this reaction, the polyamic acids and the polyimides become insoluble. The polyamic acids and the polyimides crosslinked by the polycondensation show remarkably improved heat resistance. Unlike conventional photosensitive polyimides which are crosslinked by the radical reaction, the photosensitive resin composition of the present invention is crosslinked by polycondensation with oxidation of the cis-diene structure by the singlet oxygen. Therefore, the reaction is not adversely affected by oxygen in the air and the crosslinked resin has excellent heat resistance.
The oxygen sensitizer used for the composition of the present invention is not particularly limited. It is preferable that the oxygen sensitizer has an excited triplet energy of 22.5 kcal/mol or more. Examples of the oxygen sensitizer include methylene blue, rose bengal, hematoporphyrin, tetraphenylporphine, rubrene, fullerene C60, fullerene C70 and fullerene C82. The oxygen sensitizer may be used singly or as a combination of two or more types. Among these oxygen sensitizers, fullerene C60 and fullerene C70 are preferably used.
In the composition of the present invention, the amount of the oxygen sensitizer is not particularly limited. It is preferable that the amount of the oxygen sensitizer is 0.01 to 20 parts by weight and more preferably 0.1 to 10 parts by weight per 100 parts by weight of the cis-diene-substituted polyamic acid or polyimide having a structural unit represented by any of general formulae [1] to [5]. When the amount of the oxygen sensitizer is less than the above range, there is the possibility that the sensitizing effect becomes insufficient. When the amount of the oxygen sensitizer is more than the above range, economic disadvantage arises and there is the possibility that forming a uniform film in accordance with spin coating or bar coating becomes difficult. The composition of the present invention which comprises the high molecular weight cis-diene-substituted polyamic acid or polyimide and the oxygen sensitizer has a suitable viscosity when the composition is used as a solution and can be applied to silicon wafers uniformly to a necessary thickness by a spin coater, a bar coater or a curtain coater. Because the resin layer is formed by crosslinking the high molecular weight cis-diene-substituted polyamic acid or polyimide in the composition, the formed resin layer has excellent strength and heat resistance. The expensive oxygen sensitizer such as fullerenes is used in a relatively small amount and the resin layer can be formed economically advantageously.
The method of application of the photosensitive resin composition of the present invention is not particularly limited. In general, the photosensitive resin composition is applied to a substrate, worked to form patterns by light exposure and development and then, where necessary, heat cured to form a resin layer. The method of forming the coating film is not particularly limited. Examples of the method of forming the coating film include a method in which varnish obtained by dissolving the photosensitive resin composition into a solvent is directly applied to a substrate in accordance with spin coating, bar coating or curtain coating and the formed layer is dried under a mild condition or a method in which a varnish obtained by dissolving the photosensitive resin composition into a solvent is applied to a releasing substrate made of a plastic sheet or a sheet of a metal such as stainless steel and dried under a mild condition to prepare a material for coating and then the layer on the prepared material for coating is transferred to a substrate by lamination with pressure.
The wave length of the radiation applied to the composition of the present invention can be suitably selected in accordance with the used oxygen sensitizer. For example, when fullerene C60 is used as the oxygen sensitizer, radiation having a wide range of wave length such as light of ultraviolet region to visible region (250 to 780 nm), X-ray and electron beams can be used. The exposure can be conducted by irradiating the light to the coating film through a mask which can shield area of the formed coating film where the resin composition will be removed. After the exposure, the development can be conducted by using an organic solvent or an alkaline aqueous solution which can dissolve the resin composition not exposed to the light. The resin composition in the area not exposed to the light is dissolved while the resin composition in the exposed area has been made insoluble by the crosslinking by polycondensation. As the result, the resin layer can be worked to form patterns such as holes using the mask.
The cis-diene-substituted polyamic acids having the structural units represented by formulae [1] to [5] can be converted into polyimides by the ring closure reaction with dehydration by heat curing the polyamic acids after the development. The condition of the heat curing reaction is not particularly limited. In general, it is preferable that the reaction is conducted by heating at 150 to 250xc2x0 C. for 30 minutes or more. The heating can be conducted by using heated air, irradiation of infrared light or heated plates. The heating can be ordinarily conducted in the atmosphere of the air. Where necessary, the heating may be conducted in the atmosphere of an inert gas such as nitrogen and carbon dioxide or at a reduced pressure. It is not always necessary that the cis-diene-substituted polyimide is treated by the heat curing reaction. However, the heating at the above temperature condition gives the resin the history at high temperature and heat resistance of the resin can be improved. By using the resin composition of the present invention in the above working steps, the patterned resin layer having excellent heat resistance can be formed by working at low temperatures and printed circuit wiring boards, substrates for disposing semiconductor chips and semiconductor devices having excellent properties can be produced.
To summarize the advantages of the invention, the photosensitive resin composition of the present invention has excellent properties as a heat resistant photoresist of the negative type. The polyamic acid and the polyimide used in the composition of the present invention are soluble in solvents such as an alkaline aqueous solution in the original form. When the polyamic acid and the polyimide are crosslinked by polycondensation with oxidation of the cis-diene group at the side chain with the singlet oxygen generated by the effect of the oxygen sensitizer such as fullerene C60, the polyamic acid and the polyimide become insoluble in solvents. Therefore, practically useful patterns of the negative type can be obtained with high sensitivity and high resolution which cannot be achieved by conventional heat resist compositions. In particular, heat resistance of the resin film after formation of the patterns can be remarkably improved by using a fullerene as the oxygen sensitizer. The polyamic acid and the polyimide in which the main chain is bonded to the meta-positions of an aromatic ring substituted with a monovalent organic group having a cis-diene structure provides a resin having more excellent heat resistance than that provided by the polyamic acid and the polyimide in which the main chain is bonded to the para-positions of an aromatic ring substituted with a monovalent organic group having a cis-diene structure. The printed wiring board, the substrate for disposing semiconductor chips and the semiconductor device of the present invention which are produced by using the composition of the present invention have excellent properties.